1. Field of the Invention
The present invention concerns a safety binding for a snowboard.
2. Description of the Related Art.
Safety bindings of various design lay-outs are known as such for application on skis. For snowboards, however, generally still a normal type binding is provided for the boots (hard shell boots or soft boots) which hardly correspond to the criteria required for safety bindings. Some few types of safety bindings are available on the market presently which can fulfil the requirements for snowboards to a certain extent. Among others a safety binding type is known under the trademark xe2x80x9cMeyerxe2x80x9d which consists of a disk shaped as a spherical segment mounted onto the snowboard and provided with recesses engaging a support plate which enrages under rotation of the snowboard boot thereon. The latter is fastened to the support plate using conventional buckle straps. The support plate presents a central circular opening to be centered onto the circular disk. The support plate furthermore is provided with two rounded bolts arranged on diametrically opposed sides seen in the longitudinal direction which by means of compression springs are pre-tensioned towards the inside and thus can snap into the engaging recesses of the disk. The force excited by the individual compression springs can be pre-set by means of a setting screw. For this purpose a setting scale is provided on the support plate. As a rule the two support plates first are fastened to the spherically shaped disks by rotating them and subsequently the snowboard boots are fastened thereon using the buckle straps. If the snowboarder exerts excessive load onto the snowboard, which can be caused by a rotation of the foot about the longitudinal direction of the foot, about the longitudinal direction of the shinbone or by a combination of these rotations. the support plate then is released from the disk and foot or leg injuries thus can be prevented.
This known type of safety binding actually permits setting merely of the triggering torque moment about the longitudinal direction of the shinbone in such a manner that the other directions of rotation of the foot effect a triggering action of the safety binding always in a pre-determined ratio compared to said torque setting. This signifies that these various triggering torque moments themselves can not be pre-set individually. This can result in false release triggering actions of the safety binding which may induce experienced snowboarders to dispense with safety bindings altogether and to just rely on the usual buckle straps. The number of sports injuries caused by extreme descent style on bumpy track runs or impassable slopes thus could increase noticeably whichxe2x80x94quite apart from the painful personal sufferingsxe2x80x94is very undesirable economically.
It thus is the objective of the present invention to create a safety binding for a snowboard which precludes false release triggering altogether and thus meets with greater acceptance with snowboarders.
This objective is met using a safety binding presenting the characteristics described herein.
The safety binding according to the present invention has a locking mechanism between the first element secured to the snowboard and the second element fastened to the ski boot or snowboard boot. It comprises two compression springs extending substantially parallel to the plane of the snowboard. The ends of the compression springs are provided with a bolt meshing with an engaging element. in this arrangement the triggering torque moment in case of a rotation about the longitudinal direction of the shin-bone is governed by the two compression springs which has a decisive effect onto the triggering levels for the two other directions. Thus the occurrence of a false triggering action caused by a rotation of the foot which consists of a combination of the various rotations is excluded to a very large extent.
In an advantageous further development of the inventive safety binding, the clamping forces of the compression springs can be pre-set. In this manner individual settings can be established. Setting using a counter-plate with a spacer element which can be set by rotation, such as a screw, has proven particularly advantageous. The engaging elements advantageously have the form of a trough in such a manner that slight shifting or rotation of the first element relative to the second element can be taken up without a release action being triggered. It proves particularly advantageous to form the engaging elements as arched grooves with a recessed trough for each of the bolts. In this arrangement the bolts are more effectively guided during the snap-on engaging action. In practical use it has proven most useful that the shape of the grooves and/or the troughs can be adjusted with the help of height adjustable inserts, in particular of screws. The embodiment in which the compression springs are provided on the first part laid out as fastening plate and the engaging elements are provided on the second part formed as a boot plate presents the important advantage that great stability of the safety binding is achieved. Furthermore, the compression springs are excellently protected against snow, dirt and ice. Especially for more demanding snowboard runs it has proven useful to provide adjustability of the fastening plate over an angle of about 3xc2x0 to 10xc2x0 with respect to its longitudinal direction, in particular about 5xc2x0 and/or relative to an axis extending at right angles to the longitudinal direction over an angle of about 3xc2x0 to 10xc2x0, in particular about 5xc2x0 with respect to the plane of the snowboard. These settings, called xe2x80x9ccantingxe2x80x9d, and xe2x80x9cheelxe2x80x9d respectively, are pre-set particularly for the safety binding for the front foot and can be dispensed with for the binding of the back foot. These angles advantageously can be adjusted using two setting screws and two rubber elastic intermediate rings. Furthermore, it has proven particularly advantageous if a stopper is provided on the fastening plate which after a triggering action automatically moves to its stop position.